Setting Round-Robin Multipathing Policy in VMware ESXi 6.0

Storage Array Type Plugins (SATP) and Path Selection Plugins (PSP) are part of the VMware APIs for Pluggable Storage Architecture (PSA). The SATP has all the knowledge of the storage array to aggregate I/Os across multiple channels and has the intelligence to send failover commands when a path has failed. The Path Selection Policy can … Continue reading

What’s with MGTDB anyways

For those who have either upgraded or fresh-installed 12.1 (12c) Grid Infrastructure stack, will notice a new database instance (-MGMTDB) that was provisioned automagically. So what is this MGMTDB and why do I need this overhead. Si let’s recap what the DB is and what it does… Management Database is the central repository to store … Continue reading

Setting Jumbo Frames – Portrait of a Large MTU size

There cases where we need to ensure that large packet “address-ability” exists. This is needed to verify configuration for non standard packet sizes, i.e, MTU of 9000. For example if we are deploying a NAS or backup server across the network. Setting the MTU can be done by editing the configuration script for the relevant … Continue reading

Oracle 12c Multitentant – My Top Ten PDB Questions PartI

Q. What are my options for connecting to a Pluggable Database ? A. Connect to root, then SQL> alter session set container = nisha; Database connection using easy connect Ex: CONNECT username/password@host[:port][/service_name][:server][/instance_name] $ sqlplus test1/test123@//localhost/nisha Need to define Database connection using a net service name Example TNSNAMES.ora: ======= LISTENER_CDB1 =   (ADDRESS = (PROTOCOL = … Continue reading

[Re-] Imaging Exadata with

 [Re-] Imaging Exadata with Introduction This document, based on Doc ID 1991376.1, specifically addresses re-imaging Exadata systems to, using standard (non-OVM) deployment via USB boot.  In this scenario, a new Exadata system was delivered with the image; however, client decided to implement the latest image ( before OEDA was executed. Scenario The … Continue reading

Installing Oracle Linux 6.6, Prepping Linux OS for Oracle Database 12c Install, and Installing Oracle Database 12c

Installing Oracle Linux 6.6, Prepping Linux OS for Oracle Database 12c Install, and Installing Oracle Database 12c I know it seems simple to install Linux and Oracle Dtaabase. But I felt a need to standardize on how we do it internally at Viscosity. So I provided this little note to our DBA team to build … Continue reading

Apply 12102 PSU1 (19392646) on a Standalone Cluster

We are about to apply 12102 PSU1 (19392646) on a Standalone Cluster. This patch applies the patch to RDBMS home as part of opatchauto. Here’s the output in case anyone wants to compare: [root@ol64afd OPatch]# ./opatchauto apply -analyze /mnt/hgfs/12cGridSoftware/12102-PSU1/19392646 -ocmrf ocm/bin/ocm.rsp OPatch Automation Tool Copyright (c) 2014, Oracle Corporation. All rights reserved. OPatchauto version : … Continue reading

blktrace basics

Life of an I/O Once a user issues an I/O request, this I/O enters block layer…then the magic begins… 1. IO request is remapped atop underlying logical/aggregated device device (MD, DM). Depending on alignment, size, …, requests are split into 2 separate I/Os 2. Requests added to the request queue 3. Merged with a previous … Continue reading

ASM Check script

Here’s a little script from @racdba that does ASM check when we go onsite #!/bin/ksh HOST=`hostname` ASM_OS_DEV_NM=/tmp/asmdevicenames.log ASMVOTEDSK=/tmp/asm_votingdisks.log GRID_HOME=`cat /etc/oratab |grep “+ASM” |awk -F “:” ‘{print $2}’` ORACLE_HOME=$GRID_HOME PATH=$ORACLE_HOME/bin:$PATH: export GAWK=/bin/gawk # # do_pipe () { SQLP=”$GRID_HOME/bin/sqlplus -s / as sysdba”; $SQLP |& # Open a pipe to SQL*Plus print -p — ‘set feed off … Continue reading

iSCSI and enable disks for ASM

Helpful tips for my iSCSI storage buds that want to enable/provision disks for ASM # get initiator name of host or hosts cat /etc/iscsi/initiatorname.iscsi # create volume on san and present to host login to san, create volume, add initator(s) to access # get wwid for each disk and update alias in multipath.conf multipath -ll … Continue reading

These questions keep coming up, so for quick reference, here’s a terminology re-cap!! ZFS Snapshots and Clones Snapshots A snapshot is a point-in-time copy of a filesystem or LUN. Snapshots can be created manually or by setting up an automatic schedule. Snapshots initially consume no additional space, but as the active share changes, previously unreferenced … Continue reading

Creating PDBs part 3

Due to so many people asking me other methods besides SQLplus for provisioning PDBs; such as OEM, DBCA, etc. In this blog entry I’ll DBCA, just because its simple to show. As I mentioned in my last PDB blog, the installer DBCA (initial DBA invocation) looks different than the subsequent (post initial db creation). The … Continue reading

Creating PDB’s part 2

Once we have installed 12.1 Database Software, we can create the Container Database and the Pluggable Databases. In my case I did a software only install then manually executed DBCA In this blog entry I’ll show the screens that walk-thru the configuration of the “first” database. I noticed that once DBCA is used to create … Continue reading

Creating PDBs

Consolidate where possible …Isolate where necessary In the last blog I mentioned the benefits of schema consolidation and how it dove tails directly into a 12c Oracle Database PDB implementation. In this part 2 of the PDB blog, we will get a little more detailed and do a basic walk-through, from “cradle to grave” of … Continue reading

12c PDB Multitenancy, Schema Consolidation, and whatever

Many of you have probably have heard me speak over the years (at OOW, local user groups and at the local bars) about the virtues of simplification, rationalization, and consolidation. I mentioned the different database consolidation and multi-tenancy models: Virtualization based, Database Instance and Schema consolidation. The following papers I wrote [when I was at … Continue reading

How to recover from an aborted GI Standalone Clusterware config …and live to tell about it

I generally don’t get time to play with single instance ASM since I in live the RAC world so much. But I needed to quickly create a 12c PDB configuration over ASM. If you recall from the 11gR2 tho is straightforward install and configuration of Grid Infrustructure. However, there are cases where the install/config doesn’t … Continue reading


Even though Nitin presented a session on Oracle 12c ASM New Features at IOUG Collaborate 2013, he was not allowed to submit any documentation since Oracle 12c was not GA yet. Here’s his paper on ASM 12c New Features – The New ASM Frontier Posted by Nitin Vengurlekar, Viscosity North America, CTO

My new Favorite RAC-Clusterware command

My new favorite 12c Oracle Clusterware command is the ‘crsctl stat res “resource name” -dependency’ What this command does, is to provide a dependency tree structure for resource the in question. This will display startup (default) and shutdown dependencies. From this we can understand the pull-up, pushdown, weak, and hard dependencies between clusterware resources [oracle@rac02 … Continue reading